Arduino Forum

I found this in the source code for pulseIn():"/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH * or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds * to 3 minutes in length, but must be called at least a few dozen microseconds * before the start of the pulse. */"

However, this is *not* in the documentation here: http://arduino.cc/en/Reference/PulseIn (http://arduino.cc/en/Reference/PulseIn)

Please update the documentation to contain the above information, which is critical for certain applications. The line I especially found useful from the source code is that the function "must be called at least a few dozen microseconds before the start of the pulse."